XD-374 Add command to list taps

* Add several utility classes for rendering textual contents to the console (E.g. text tables). Migrated from Cloud Foundry Maven Plugin / Hadoop Samples project.
* Align rendering of the Spring XD Shell banner with the Spring Rest Shell
* Add several missing package-info.java files

XD-374 Code review + add tests
XD-466 Add Json support to Tuple
XD-466 - renamed JSon to Json and minor changes per PR review comments
XD-466 - revert build.gradle
XD-476 correct the AbstractRedisRepository to delete the correct key based on the repoPrefix
XD-388 Add webhdfs dependencies to classpath

Add jar files needed to use webhdfs for hdfs sink
Merge branch 'XD-476' of github.com:datianshi/spring-xd into datianshi-XD-476
Merge branch 'XD-466'
Fix Taps to actually use the Resource
renamed JSon to Json...
Implemented Stream listing from Shell (no Pagination yet)
XD-496 - added DefaultTupleConversionService
Merge branch 'XD-496'
XD-469 Upgrading to spring-data-hadoop 1.0.1.RC1
Fixing some inconsistencies in commands help + added test on those + added ability to generate Shell reference in doco build
XD-478 Add Accepted Mediatype Support in Module